This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We are investigating the structure of the U2-U6 snRNA complex from S. cerevisiae. This large RNA complex has been highly conserved throughout eukaryotic evolution, and forms the catalytic core of the spliceosome. The RNA structure will be investigated at a range of temperatures, pH and ionic conditions. NMR experiments that we will need to collect include: 1D (1H), 2D NOESY, 2D 1H-15N HSQC (normal and TROSY enhanced), 2D 1H-15N HNN COSY, 2D 1H-13C HSQC (normal and TROSY enhanced), 2D NOESY, 2D 1H,13C filter/edit NOESY. Residual dipolar couplings will be measured for samples in both isotropic and partially aligned states (via addition of Pf1 phage).